For economic reasons, rotary beverage receptacle-filling apparatus is operated at the limit of output, that is, at very high rates. In the process, problems arise in accurately maintaining the desired nominal filling level in the receptacles. A number of methods of monitoring the filling procedure are known from the state of the art.
German patent document 30 36 294 A1 describes beverage receptacle-filling apparatus comprising devices in the filling means to measure the flow, i.e., the rate at which liquid passes, these devices feeding their values to a central computer which calculates the time for terminating flow and at that time closes flow control members. In addition a monitoring device for the filling level in the form of a measuring stop is present at the discharge of the beverage receptacle-filling apparatus to feed correction values to the computer for regulating the filling components. The drawback of this design is that each filling component must be fitted with flowmeters.
Beverage receptacle-filling apparatus also is known from German patent document 31 50 183 C1 which also comprises a filling level monitor at the discharge. In this design an analyzer identifies those filling components that are filling improperly. This design does not provide control of the filling level.
Designs described in German patent document 32 18 062 A1 are widely used in the state of the art, each filling component comprising a probe dipping into the receptacle to measure the filling level. When reaching the limit level, the probe actuates a control driving the flow of beverage. This design also incurs the drawback of substantial complexity for each of the filling components which, in conventional beverage receptacle-filling apparatus, are present in large numbers.
Another apparatus is shown in German patent document 31 15 957 A1 in which meters for the filling level are stationary next to the beverage receptacle-filling apparatus and are able to transiently operate on the passing receptacles. If the limit level has been reached in one of the sensed receptacles, then a transmitter located in the same angular position as the meter transmits a closing control signal to a receiver which at this time is directly adjacent to the filling component of the beverage receptacle-filling apparatus.
Such a system can sense a receptacle only transiently in a specific angular position relative to the beverage receptacle-filling apparatus. If there were only one such system, then it would only determine each time that the filling level is too high or too low. In this system, therefore, such systems must be mounted next to one another in large numbers to allow detecting the nominal level having been reached in at least one system when monitoring the slowly rising filling level of several receptacles passing such an arrangement.
This design incurs the drawback of the large hardware cost caused by the plurality of complex systems and the receivers required at each filling component.
Lastly the use of video cameras with image analyzers is known for purposes other than those stated herein. Illustratively, as shown in German patent document 32 12 432 C2, inspection means preceding or following beverage receptacle-filling apparatus may monitor receptacles for intactness, filling state or the like, and according to the German patent document 40 30 081 A1, they may monitor the foaming conditions inside receptacles following the beverage receptacle-filling apparatus in order to control the foaming process. In this state of the art the video cameras always are designed and mounted in such a way that they cover only one receptacle at a time.